When roaming on AT&T anywhere in the Cleveland Ohio area, all towers, I can't send text messages. Calls are fine. If I'm on a T-Mobile tower (or if I forcefully choose T-mobile from the carriers list) text messages send/receive fine. I hope someone can look into this.
Sim card removal created no change. Thank you for the suggestion tho. Koodo should be contacting AT&T to ensure roaming agreements are being upheld for their large customer base. AT&T isn't going to care enough to investigate about a single issue from a customer from another network and another country.
Hey Bob! You mentioned that you had an iPhone..are you trying to send texts to other iPhones users? Maybe your phone is trying to send it as an iMessage, which requires data. Try turning off iMessage (Settings ->Messages->iMessage) and check to see if that helps. Keep us posted!